U.S. patent application number 12/900867 was filed with the patent office on 2011-04-14 for surface texture measuring machine and a surface texture measuring method.
This patent application is currently assigned to MITUTOYO CORPORATION. Invention is credited to Sadaharu ARITA, Yasushi FUKUMOTO, Kotaro HIRANO, Koichi KOMATSU, Sadayuki MATSUMIYA, Yoshiyuki OMORI, Fumihiro TAKEMURA.
Application Number | 20110083497 12/900867 |
Document ID | / |
Family ID | 43437242 |
Filed Date | 2011-04-14 |
United States Patent
Application |
20110083497 |
Kind Code |
A1 |
MATSUMIYA; Sadayuki ; et
al. |
April 14, 2011 |
SURFACE TEXTURE MEASURING MACHINE AND A SURFACE TEXTURE MEASURING
METHOD
Abstract
A surface texture measuring machine includes: a stage, a
contact-type detector having a stylus, an image probe, a relative
movement mechanism and a controller. The controller includes: a
center position calculating unit that, when the image probe enters
position data of at least three points on a circular contour of a
circular concave portion or a circular convex portion of an object,
approximates the entered position data to a circle to obtain a
center position of the circle; and a stylus setting unit that,
after calculating the center position, operates the relative
movement mechanism to position the stylus of the contact-type
detector at the center position.
Inventors: |
MATSUMIYA; Sadayuki;
(Kawasaki-shi, JP) ; OMORI; Yoshiyuki; (Kure-shi,
JP) ; ARITA; Sadaharu; (Kure-shi, JP) ;
HIRANO; Kotaro; (Kawasaki-shi, JP) ; FUKUMOTO;
Yasushi; (Kawasaki-shi, JP) ; KOMATSU; Koichi;
(Kawasaki-shi, JP) ; TAKEMURA; Fumihiro;
(Kawasaki-shi, JP) |
Assignee: |
MITUTOYO CORPORATION
Kawasaki-shi
JP
|
Family ID: |
43437242 |
Appl. No.: |
12/900867 |
Filed: |
October 8, 2010 |
Current U.S.
Class: |
73/105 |
Current CPC
Class: |
G01B 11/245 20130101;
G01B 5/008 20130101; G01B 11/005 20130101; G01B 21/047
20130101 |
Class at
Publication: |
73/105 |
International
Class: |
G01B 5/28 20060101
G01B005/28 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 13, 2009 |
JP |
2009-236121 |
Oct 13, 2009 |
JP |
2009-236123 |
Oct 13, 2009 |
JP |
2009-236124 |
Oct 13, 2009 |
JP |
2009-236125 |
Claims
1. A surface texture measuring machine for measuring a surface
texture of an object, comprising: a stage on which the object is
mounted; a contact-type detector having a stylus that is brought
into contact with a surface of the object; an image probe that
captures an image of the surface of the object; a relative movement
mechanism that relatively moves the stage against the contact-type
detector and the image probe and/or relatively moves the
contact-type detector and the image probe against the stage; and a
controller that controls a drive of the relative movement mechanism
and executes processing on measurement data obtained by the
contact-type detector and image data captured by the image probe,
the controller including: a center position calculating unit that,
when the image probe enters position data of at least three points
on a circular contour of a circular concave portion or a circular
convex portion of the object, approximates the entered position
data to a circle to obtain a center position of the circle; and a
stylus setting unit that, when the center position calculating unit
obtains the center position, operates the relative movement
mechanism to position the stylus of the contact-type detector at
the center position.
2. The surface texture measuring machine according to claim 1,
wherein one of the stylus of the contact-type detector and the
image probe is located at an offset position not to interfere with
the other of the stylus of the contact-type detector and the image
probe which is to be measured, the surface texture measuring
machine further comprising: an offset amount storage unit that
stores an offset amount of a tip end of the stylus of the
contact-type detector and the image probe, and when the center
position is obtained by the center position calculating unit, the
stylus setting unit operates the relative movement mechanism to
position the image probe at the center position and then operates
the relative movement mechanism by the offset amount stored in the
offset amount storage unit to position the stylus of the
contact-type detector at the center position.
3. A surface texture measuring method for measuring a surface
texture of an object having a circular concave portion or a
circular convex portion by using a surface texture measuring
machine comprising: a stage on which the object is mounted; a
contact-type detector having a stylus that is brought into contact
with a surface of the object; an image probe that captures an image
of the surface of the object; a relative movement mechanism that
relatively moves the stage against the contact-type detector and
the image probe and/or relatively moves the contact-type detector
and the image probe against the stage; and a controller that
controls a drive of the relative movement mechanism and executes
processing on measurement data obtained by the contact-type
detector and image data captured by the image probe, the surface
texture measuring method comprising: acquiring position data of at
least three points on a circular contour of the circular concave
portion or the circular convex portion of the object by the image
probe by operating the relative movement mechanism; approximating
the position data to a circle to obtain a center position of the
circle; operating the relative movement mechanism to position the
stylus of the contact-type detector at the center position; and
measuring the surface texture of the circular concave portion or
the circular convex portion of the object while relatively moving
the stylus of the contact-type detector and the object by operating
the relative movement mechanism after the stylus of the
contact-type detector is positioned at the center position of the
circular concave portion or the circular convex portion of the
object.
4. A surface texture measuring machine for measuring a surface
texture of an object after adjusting an attitude of the object in
parallel to or perpendicular to a predetermined measurement axis,
comprising: a stage provided with a turntable on which the object
is mounted, the turntable rotating the object within a
predetermined plane; a contact-type detector having a stylus that
is brought into contact with a surface of the object; an image
probe that captures an image of the surface of the object; a
relative movement mechanism that relatively moves the turntable and
the contact-type detector; and a controller that controls the
relative movement mechanism and the turntable, the controller
including: an image probe control unit that captures the image of
the object by the image probe; an inclination calculating unit that
calculates an inclination angle of the object relative to the
measurement axis based on the image of the object captured by the
image probe control unit; and an attitude adjusting unit that
rotates the turntable based on the inclination angle calculated by
the inclination calculating unit and adjusts the attitude of the
object in parallel to or perpendicular to the measurement axis.
5. A surface texture measuring machine for measuring a surface
texture of an object after adjusting an attitude of the object in
parallel to or perpendicular to a predetermined measurement axis,
comprising: a stage provided with a leveling table on which the
object is mounted, the leveling table inclining the object relative
to a reference plane perpendicular to a displacing direction of a
stylus; a contact-type detector having the stylus that is brought
into contact with a to-be-measured surface of the object; an image
probe that captures an image of a surface of the object; a relative
movement mechanism that relatively moves the leveling table and the
contact-type detector; a controller that controls the relative
movement mechanism and the leveling table, the controller
including: a focusing unit that moves the image probe in a
direction perpendicular to the reference plane at a plurality of
points of the to-be-measured surface by the relative movement
mechanism and determines a focal point of the image probe at each
of the points; an inclination calculating unit that calculates an
inclination angle of the to-be-measured surface relative to the
reference plane based on a position perpendicular to the reference
plane of the image probe at the each of the points; and an attitude
adjusting unit that inclines the leveling table based on the
inclination angle calculated by the inclination calculating unit
and adjusts the attitude of the object so that the to-be-measured
surface is in parallel to the reference plane.
6. The surface texture measuring machine according to claim 1,
wherein the controller includes: a movement course calculating unit
that, when a measurement starting position on the object is
designated based on the image of the object captured by the image
probe, calculates and stores a movement course of the relative
movement mechanism so that the stylus of the contact-type detector
is brought into contact with the measurement starting position on
the object; and a stylus setting unit that operates the relative
movement mechanism to follow the movement course calculated by the
movement course calculating unit.
7. The surface texture measuring machine according to claim 4,
wherein the controller includes: a movement course calculating unit
that, when a measurement starting position on the object is
designated based on the image of the object captured by the image
probe, calculates and stores a movement course of the relative
movement mechanism so that the stylus of the contact-type detector
is brought into contact with the measurement starting position on
the object; and a stylus setting unit that operates the relative
movement mechanism to follow the movement course calculated by the
movement course calculating unit.
8. The surface texture measuring machine according to claim 5,
wherein the controller includes: a movement course calculating unit
that, when a measurement starting position on the object is
designated based on the image of the object captured by the image
probe, calculates and stores a movement course of the relative
movement mechanism so that the stylus of the contact-type detector
is brought into contact with the measurement starting position on
the object; and a stylus setting unit that operates the relative
movement mechanism to follow the movement course calculated by the
movement course calculating unit.
9. The surface texture measuring machine according to claim 6,
wherein the image probe includes a probe body and a probe head that
is supported at a tip end of the probe body and is capable of
capturing the image of the object, the probe head being attached to
the probe body in a manner to be rotatable around an axis
perpendicular to a direction of the relative movement of the
contact-type detector and the stage and a displacing direction of
the stylus when the stylus is in contact with the object.
10. The surface texture measuring machine according to claim 7,
wherein the image probe includes a probe body and a probe head that
is supported at a tip end of the probe body and is capable of
capturing the image of the object, the probe head being attached to
the probe body in a manner to be rotatable around an axis
perpendicular to a direction of the relative movement of the
contact-type detector and the stage and a displacing direction of
the stylus when the stylus is in contact with the object.
11. The surface texture measuring machine according to claim 8,
wherein the image probe includes a probe body and a probe head that
is supported at a tip end of the probe body and is capable of
capturing the image of the object, the probe head being attached to
the probe body in a manner to be rotatable around an axis
perpendicular to a direction of the relative movement of the
contact-type detector and the stage and a displacing direction of
the stylus when the stylus is in contact with the object.
Description
[0001] The entire disclosure of Japanese Patent Applications No.
2009-236121 filed Oct. 13 2009, No. 2009-236123 filed Oct. 13 2009,
No. 2009-236124 filed Oct. 13 2009, and No. 2009-236125 filed Oct.
13 2009, are expressly incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a surface texture measuring
machine for measuring surface profiles, surface roughness and the
like of an object to be measured and a surface texture measuring
method. Specifically, the present invention relates to a surface
texture measuring machine including a contact-type detector
provided with a stylus and an image probe, and a surface texture
measuring method.
[0004] 2. Description of Related Art
[0005] There has been known a surface texture measuring machine in
which a stylus is moved along a surface of an object while being in
contact with the surface of the object. A displacement of the
stylus due to a surface profile or surface roughness of the object
is detected, thereby measuring the surface profile, surface
roughness and the like of the object based on the displacement of
the stylus (see, for instance, Patent Literature:
JP-A-05-087562).
[0006] In such a typical surface texture measuring machine, in
order to measure the surface profile, surface roughness and the
like of the object, while visually checking and adjusting a
relative position between a tip end of a stylus and a measurement
area on the object, an operator sets the tip end of the stylus at a
measurement starting position on the object and then moves the
stylus along the surface of the object. A surface texture such as
the surface profile and the surface roughness of the object is
measured based on a vertical displacement of the stylus due to the
surface profile, surface roughness and the like of the object.
[0007] Moreover, in the surface texture measuring machine, when an
attitude of the object is inclined relative to a measurement axis
in measuring a surface of the object, a measurement result may have
an error. For instance, when an attitude of a cylinder is inclined
relative to a measurement axis in measuring an axial texture of a
surface of the cylinder, a stylus is displaced in an outer
circumferential direction of the cylinder as well as in an axial
direction of the cylinder while the stylus is moved along the
measurement axis. For this reason, a measurement value includes a
value showing an outer circumferential texture of the cylinder as
well as a value showing an axial concavity and convexity of the
surface of the cylinder, so that the measurement result has an
error. Moreover, in the surface texture measuring machine, when a
to-be-measured surface is inclined relative to a horizontal plane,
the measurement result may also have an error.
[0008] Accordingly, there has been developed a surface texture
measuring machine that performs a preliminary measurement of an
object with a stylus before an actual measurement and adjusts an
attitude of the object, for instance, in parallel to a measurement
axis based on a result of the preliminary measurement (for
instance, Patent Literature 2: JP-A-2000-266534). The surface
texture measuring machine of Patent Literature 2 includes a
turntable that rotates the object on a horizontal plane. The
surface texture measuring machine rotates the turntable based on
the result of the preliminary measurement performed with the stylus
and adjusts the attitude of the object in parallel to the
measurement axis (so-called alignment).
[0009] Also, the surface texture measuring machine of Patent
Literature 2 includes a leveling table that inclines the object
relative to the horizontal plane. The surface texture measuring
machine inclines the leveling table based on the result of the
preliminary measurement performed with the stylus and adjusts the
attitude of the object so that the to-be-measured surface thereof
is horizontal (so-called leveling).
[0010] Due to a recent tendency for measuring minute and thin
objects, objects or measuring spots are downsized. Accordingly, the
above setting operation of a stylus, which is quite complicated and
requires a long time, places a large burden on the operator.
[0011] In addition, some types of objects may interfere with
(collide with) a stylus to damage the stylus or the objects.
[0012] Particularly, as shown in FIGS. 18A to 18C, in measuring a
radius or diameter of each of a plurality of microlens molding
surfaces 72 having convexity (or concavity) of 1 mm or less
diameter that are formed on a microlens array mold 71, the stylus
must correctly trace a center line where vertexes (peak or bottom
points) of the microlens molding surfaces 72 are located in order
to obtain a correct measurement result.
[0013] In order to measure such an object, as shown in FIGS. 19A to
19C, in a typical measurement, the operator is required to position
a tip end of a stylus 24 on the microlens molding surface 72 while
visually checking a relative position between the tip end of the
stylus 24 and the microlens molding surface 72 (see FIG. 19A), to
move a stage on which the microlens array mold 71 (the object) is
mounted (see FIG. 19B), to detect the vertex of the microlens
molding surface 72 (see FIG. 19C), and to relatively move the
stylus 24 so as to trace the center line of the microlens molding
surface 72.
[0014] For this reason, in a typical operation, a setting time of
the stylus is extremely longer than a measuring time (for instance,
the measuring time is approximately 10 seconds and the setting time
is approximately 120 seconds).
[0015] Moreover, in the surface texture measuring machine of Patent
Literature 2, it takes extremely long time for the preliminary
measurement because the preliminary measurement requires many steps
and uses the stylus for measuring the surface of the object.
Further, the object may be damaged by the stylus.
SUMMARY OF THE INVENTION
[0016] An object of the invention is to provide a surface texture
measuring machine for shortening a setting time of a stylus and a
surface texture measuring method for the same.
[0017] Another object of the invention is to provide a surface
texture measuring machine for shortening a time in a preliminary
measurement and not damaging an object in the preliminary
measurement.
[0018] According to an aspect of the invention, a surface texture
measuring machine for measuring a surface texture of an object
includes: a stage on which an object is mounted; a contact-type
detector having a stylus that is brought into contact with a
surface of the object; an image probe that captures an image of the
surface of the object; a relative movement mechanism that
relatively moves the stage against the contact-type detector and
the image probe and/or relatively moves the contact-type detector
and the image probe against the stage; and a controller that
controls a drive of the relative movement mechanism and executes
processing on measurement data obtained by the contact-type
detector and image data captured by the image probe, in which the
controller includes: a center position calculating unit that, when
the image probe enters position data of at least three points on a
circular contour of a circular concave portion or a circular convex
portion of the object, approximates the entered position data to a
circle to obtain a center position of the circle; and a stylus
setting unit that, when the center position calculating unit
obtains the center position, operates the relative movement
mechanism to position a stylus of the contact-type detector at the
center position.
[0019] With this arrangement, firstly, an operator operates the
relative movement mechanism and acquires the position data of at
least three points on the circular contour of the circular concave
portion or the circular convex portion of the object by using the
image probe.
[0020] Then, the controller approximates the inputted position data
to a circle to obtain the center position of the circle (a center
position calculating unit) and operates the relative movement
mechanism to position the stylus of the contact-type detector at
the center position (a stylus setting unit).
[0021] Accordingly, the stylus of the contact-type detector can be
automatically set at the center position of the circular concave
portion or the circular convex portion of the object. In other
words, the operator does not have to position the tip end of the
stylus on a microlens molding surface while visually checking and
adjusting the position of the tip end of the stylus relative to the
microlens molding surface as in a typical apparatus, thereby
shortening the setting time of the stylus.
[0022] In the surface texture measuring machine according to the
aspect of the invention, one of the stylus of the contact-type
detector and the image probe is located at an offset position not
to interfere with the other of the stylus of the contact-type
detector and the image probe which is to be measured, the surface
texture measuring machine further including an offset amount
storage unit that stores an offset amount of a tip end of the
stylus of the contact-type detector and the image probe, and when
the center position is obtained by the center position calculating
unit, the stylus setting unit operates the relative movement
mechanism to position the image probe at the center position and
then operates the relative movement mechanism by the offset amount
stored in the offset amount storage unit to position the stylus of
the contact-type detector at the center position.
[0023] With this arrangement, since one of the stylus of the
contact-type detector and the image probe is located at an offset
position not to interfere with the other of the stylus and the
image probe that is used for the measurement, the measurement is
not affected even without providing a mechanism for evacuating one
of the stylus and the image probe that is not used for the
measurement.
[0024] Further, the offset amounts between the tip end of the
stylus of the contact-type detector and the image probe are stored
in the offset amount storage unit. Accordingly, by moving the
relative movement mechanism by the offset amounts stored in the
offset amount storage unit after calculating the center position of
the circular concave portion or the circular convex portion and
positioning the image probe at the center position by operating the
relative movement mechanism, the stylus of the contact-type
detector can be automatically positioned at the center
position.
[0025] Accordingly, by obtaining and storing the accurate offset
amounts between the stylus of the contact-type detector and the
image probe in advance, the stylus of the contact-type detector can
be automatically positioned at the center position of the circular
concave portion or the circular convex portion with a simple
operation and processing.
[0026] According to another aspect of the invention, a surface
texture measuring method for measuring a surface texture of an
object having a circular concave portion or a circular convex
portion by using a surface texture measuring machine including: a
stage on which the object is mounted; a contact-type detector
having a stylus that is brought into contact with a surface of the
object; an image probe that captures an image of the surface of the
object; a relative movement mechanism that relatively moves the
stage against the contact-type detector and the image probe and/or
relatively moves the contact-type detector and the image probe
against the stage; and a controller that controls a drive of the
relative movement mechanism and executes processing on measurement
data obtained by the contact-type detector and image data captured
by the image probe, the surface texture measuring method including:
acquiring position data of at least three points on a circular
contour of the circular concave portion or the circular convex
portion of the object by the image probe by operating the relative
movement mechanism; approximating the position data to a circle to
obtain a center position of the circle; operating the relative
movement mechanism to position the stylus of the contact-type
detector at the center position; and measuring the surface texture
of the circular concave portion or the circular convex portion of
the object while relatively moving the stylus of the contact-type
detector and the object by operating the relative movement
mechanism after the stylus of the contact-type detector is
positioned at the center position of the circular concave portion
on the circular convex portion of the object.
[0027] With this arrangement, firstly, in the contour data
acquisition step, the relative movement mechanism is operated and
the position data of the at least three points on the circular
contour of the circular concave portion or the circular convex
portion of the object are acquired by the image probe. Then, in the
circle approximation step, the position data acquired in the
contour data acquisition step are approximated to the circle to
calculate the center position of the circle.
[0028] Next, in the stylus setting step, the relative movement
mechanism is operated and the stylus of the contact-type detector
is positioned at the center position obtained at the circle
approximation step. In the measuring step, the surface texture of
the circular concave portion or the circular convex portion is
measured while the stylus of the contact-type detector and the
object are relatively moved by operating the relative movement
mechanism.
[0029] Thus, since the center position of the circular concave
portion or the circular convex portion is known in advance, the
stylus of the contact-type detector can be set at the center
position of the circular concave portion or the circular convex
portion. In other words, the operator does not have to set the tip
end of the stylus at the measurement starting position on the
object while visually checking and adjusting the position of the
tip end of the stylus relative to the measurement area on the
object as in a typical apparatus, thereby shortening the setting
time of the stylus.
[0030] According to still another aspect of the invention, a
surface texture measuring machine for measuring a surface texture
of an object after adjusting an attitude of the object in parallel
to or perpendicular to a predetermined measurement axis includes: a
stage provided with a turntable on which the object is mounted, the
turntable rotating the object within a predetermined plane; a
contact-type detector having a stylus that is brought into contact
with a surface of the object; an image probe that captures an image
of the surface of the object; a relative movement mechanism that
enable relative movement between the turntable and the contact-type
detector; and a controller that controls the relative movement
mechanism and the turntable, the controller including: an image
probe control unit that captures the image of the object by the
image probe; an inclination calculating unit that calculates an
inclination angle of the object relative to the measurement axis
based on the image of the object capture by the image probe control
unit; and an attitude adjusting unit that rotates the turntable
based on the inclination angle calculated by the inclination
calculating unit and adjusts the attitude of the object in parallel
to or perpendicular to the measurement axis.
[0031] With this arrangement, what is carried out in the
preliminary measurement is only that the image probe captures the
image of the object to calculate the inclination angle of the
object relative to the measurement axis. Accordingly, the number of
the steps in the preliminary measurement can be decreased, thereby
shortening the time for the preliminary measurement. Moreover,
since the measurement is carried out by the image probe, the
measurement time can be shortened as compared with the measurement
by the stylus. Consequently, the time for the preliminary
measurement can be considerably shortened.
[0032] Further, since the preliminary measurement is a noncontact
measurement by the image probe, the object is not damaged.
[0033] According to further aspect of the invention, a surface
texture measuring machine for measuring a surface texture of an
object after adjusting an attitude of the object in parallel to or
perpendicular to a predetermined measurement axis includes: a stage
provided with a leveling table on which the object is mounted, the
leveling table inclining the object relative to a reference plane
perpendicular to a displacing direction of the stylus; a
contact-type detector having a stylus that is brought into contact
with a to-be-measured surface of the object; an image probe that
captures an image of the surface of the object; a relative movement
mechanism that enable relative movement between the leveling table
and the contact-type detector; and a controller that controls the
relative movement mechanism and the leveling table, the controller
including: a focusing unit that moves the image probe in a
direction perpendicular to the reference plane at a plurality of
points of the to-be-measured surface by the relative movement
mechanism and determines a focal point of the image probe at each
of the points; an inclination calculating unit that calculates an
inclination angel of the to-be-measured surface relative to the
reference plane based on a position perpendicular to the reference
plane of the image probe at the each of the points; and an attitude
adjusting unit that inclines the leveling table based on the
inclination angle calculated by the inclination calculating unit
and adjusts the attitude of the object so that the to-be-measured
surface is in parallel to the reference plane.
[0034] With this arrangement, what is carried out in the
preliminary measurement is only that the image probe is moved in a
direction perpendicular to the reference plane so that the each of
the points on the to-be-measured surface is positioned at the focal
point of the image probe and then the inclination angle of the
to-be-measured surface relative to the reference plane is
calculated based on the position of the image probe at the each of
the points in the direction perpendicular to the reference plane.
Accordingly, the number of the steps in the preliminary measurement
can be decreased, thereby shortening the time for the preliminary
measurement. Moreover, since the measurement is carried out by the
image probe, the measurement time can be shortened as compared with
the measurement by the stylus. Consequently, the time for the
preliminary measurement can be considerably shortened.
[0035] Further, since the preliminary measurement is a noncontact
measurement by the image probe, the object is not damaged.
[0036] Preferably, the surface texture measuring machine according
to the above aspect of the invention includes: a movement course
calculating unit that, when a measurement starting position on the
object is designated based on the image of the object captured by
the image probe, calculates and stores a movement course of the
relative movement mechanism so that the stylus of the contact-type
detector is brought into contact with the measurement starting
position on the object; and a stylus setting unit that operates the
relative movement mechanism to follow the movement course
calculated by the movement course calculating unit.
[0037] With this arrangement, the image of the object is initially
captured by the image probe. Subsequently, when the measurement
starting position on the object is designated based on the captured
image of the object, the movement course calculating unit
calculates and stores the movement course of the relative movement
mechanism so that the stylus of the contact-type detector is
brought into contact with the measurement starting position on the
object. When a measurement is performed later, the relative
movement mechanism is moved in accordance with the movement course
calculated by the movement course calculating unit. In other words,
the relative movement mechanism is moved in accordance with the
stored movement course, thereby bringing the stylus of the
contact-type detector into contact with the measurement starting
position on the object.
[0038] In this manner, the stylus of the contact-type can be
automatically set at the measurement starting position on the
object. In other words, the operator does not have to set the tip
end of the stylus at the measurement starting position on the
object while visually checking and adjusting the position of the
tip end of the stylus relative to the measurement starting position
on the object as in a typical apparatus. Therefore, the stylus can
be prevented from interfering with the object while reducing the
burden on the operator.
[0039] In the surface texture measuring machine according to the
above aspect of the invention, the image probe preferably includes
a probe body and a probe head that is supported at a tip end of the
probe body and is capable of capturing the image of the object, the
probe head being attached to the probe body in a manner to be
rotatable around an axis perpendicular to a direction of the
relative movement of the contact-type detector and the stage and a
displacing direction of the stylus when the stylus is in contact
with the object.
[0040] With this arrangement, particularly, the image probe
includes the probe body and the probe head that is supported at the
tip end of the probe body and is capable of capturing the image of
the object. The probe head is attached to the probe body in a
manner to be rotatable around the axis perpendicular to the
direction in which the contact-type detector and the stage are
relatively moved (i.e., a trace direction) and the displacing
direction of the stylus when the stylus is in contact with the
object. Accordingly, by rotating the probe head around the axis,
the probe head can be oriented in the displacing direction of the
stylus and a direction perpendicular to the displacing
direction.
[0041] When the probe head is oriented in the displacing direction
of the stylus, for instance, an image of the object from a
horizontal surface can be captured. When the probe head is oriented
in the direction perpendicular to the displacing direction of the
stylus, an image of the object from a vertical surface can be
captured. Accordingly, even at a measurement of an inner surface
texture of a hole formed on the vertical surface, by capturing the
image of the vertical surface of the object by using the image
probe, the stylus can be accurately positioned inside the hole
formed on the vertical surface. Therefore, the stylus can be
prevented from interfering with the object while reducing the
burden on the operator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a perspective view showing a surface texture
measuring machine according to a first exemplary embodiment of the
present invention.
[0043] FIG. 2 is an enlarged perspective view showing a
contact-type detector and an image probe according to the first
exemplary embodiment.
[0044] FIG. 3 is a front view showing the contact-type detector and
the image probe according to the first exemplary embodiment.
[0045] FIG. 4 shows the image probe according to the first
exemplary embodiment.
[0046] FIG. 5 is a block diagram showing a control system according
to the first exemplary embodiment.
[0047] FIG. 6A shows an object to be measured according to the
first exemplary embodiment.
[0048] FIG. 6B shows the object to be measured according to the
first exemplary embodiment.
[0049] FIG. 7A shows the image probe being moved near the object in
the first exemplary embodiment.
[0050] FIG. 7B shows the image probe being moved near the object in
the first exemplary embodiment.
[0051] FIG. 8A shows acquisition of position data of a circular
contour in the first exemplary embodiment.
[0052] FIG. 8B shows acquisition of position data of the circular
contour in the first exemplary embodiment.
[0053] FIG. 9 shows an approximation step to a circle in the first
exemplary embodiment.
[0054] FIG. 10 shows the image probe being moved to a center
position in the first exemplary embodiment.
[0055] FIG. 11 shows a stylus being moved to the center position in
the first exemplary embodiment.
[0056] FIG. 12 shows another object to be measured according to the
first exemplary embodiment.
[0057] FIG. 13 shows the image probe being moved near the object
shown in FIG. 12 in measuring the object.
[0058] FIG. 14A shows acquisition of position data of a circular
contour in the measurement of the object shown in FIG. 12.
[0059] FIG. 14B shows acquisition of position data of the circular
contour in the measurement of the object shown in FIG. 12.
[0060] FIG. 15 shows the image probe being moved to another
position in the measurement of the object shown in FIG. 12.
[0061] FIG. 16 shows an approximation step to a circle in the
measurement of the object shown in FIG. 12.
[0062] FIG. 17 shows the stylus being moved to the center position
in the first exemplary embodiment.
[0063] FIG. 18A is an illustration showing a measurement of a
microlens mold.
[0064] FIG. 18B is another illustration showing the measurement of
the microlens mold.
[0065] FIG. 18C is further illustration showing the measurement of
the microlens mold.
[0066] FIG. 19A shows an example of a measurement of a microlens
mold by a typical measuring method.
[0067] FIG. 19B shows the example of the measurement of the
microlens mold by the typical measuring method.
[0068] FIG. 19C shows the example of the measurement of the
microlens mold by the typical measuring method.
[0069] FIG. 20 is a perspective view showing a surface texture
measuring machine according to a second exemplary embodiment of the
invention.
[0070] FIG. 21 is a block diagram showing a control system
according to the second exemplary embodiment.
[0071] FIG. 22 is a flow chart for describing an attitude
adjustment method.
[0072] FIG. 23 is a plan view showing an image probe and an object
to be measured.
[0073] FIG. 24 is a plan view showing an attitude adjustment of the
object by an attitude adjusting unit.
[0074] FIG. 25 is a plan view showing an actual measurement by a
controller.
[0075] FIG. 26 is a plan view showing the image probe that captures
an image of the object.
[0076] FIG. 27 is a plan view showing an attitude adjustment of the
object by the attitude adjusting unit.
[0077] FIG. 28 is a perspective view showing the surface texture
measuring machine according to the second exemplary embodiment of
the invention in which a turntable is replaced with a leveling
table.
[0078] FIG. 29 is a block diagram showing a controller of the
surface texture measuring machine shown in FIG. 28.
[0079] FIG. 30 is a flow chart for showing an attitude adjustment
method by the surface texture measuring machine shown in FIG.
28.
[0080] FIG. 31A is a side elevation of the leveling table of the
surface texture measuring machine shown in FIG. 28 during
operation.
[0081] FIG. 31B is a side elevation of the leveling table of the
surface texture measuring machine shown in FIG. 28 during
operation.
[0082] FIG. 32 is a perspective view showing a surface texture
measuring machine according to a third exemplary embodiment of the
invention.
[0083] FIG. 33 shows an image probe according to the third
exemplary embodiment.
[0084] FIG. 34 shows an object to be measured according to the
third exemplary embodiment.
[0085] FIG. 35A is an illustration showing a measurement of a hole
of a vertical wall by the surface texture measuring machine
according to the third exemplary embodiment.
[0086] FIG. 35B is another illustration showing the measurement of
the hole of the vertical wall by the surface texture measuring
machine according to the third exemplary embodiment.
[0087] FIG. 36A is an illustration showing a measurement of a hole
of an inclined wall by the surface texture measuring machine
according to the third exemplary embodiment.
[0088] FIG. 36B is another illustration showing the measurement of
the hole of the inclined wall by the surface texture measuring
machine according to the third exemplary embodiment.
[0089] FIG. 37 is an illustration showing a measurement of a hole
of a horizontal wall by the surface texture measuring machine
according to the third exemplary embodiment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
First Exemplary Embodiment
Description of Surface Texture Measuring Machine (see FIGS. 1 to
5)
[0090] As shown in FIGS. 1 and 2, a surface texture measuring
machine according to a first exemplary embodiment of the invention
includes: a mount stand 1; a base 2 being fixed on an upper surface
of the mount stand 1; a stage 10 being mounted on the base 2, the
stage 10 having an upper surface on which an object is mounted; a
contact-type detector 20 being provided with a stylus 24 that is
brought into contact with a surface of the object; an image probe
30 capturing an image of the surface of the object; a relative
movement mechanism 40 that relatively moves the stage 10 against
the contact-type detector 20 and the image probe 30 and moves the
contact-type detector 20 and the image probe 30 against the stage
10; and a controller 50.
[0091] The relative movement mechanism 40 includes: a Y-axis
driving mechanism 41 as a first movement mechanism being located
between the base 2 and the stage 10 to move the stage 10 in a
horizontal direction (Y-axis direction); a column 42 that stands
upright on an upper surface of the base 2; a Z-slider 43 as a
lifting member being provided to the column 42 movably in a
vertical direction (Z-axis direction); a Z-axis driving mechanism
44 as a second movement mechanism that drives the Z-slider 43 to
move in the vertical direction; a rotary plate 46 being provided to
the Z-slider 43 via a rotation mechanism 45 (see FIG. 5) so as to
be rotatable around a Y-axis; an X-slider 47 as a slide member
being provided to the rotary plate 46 so as to be movable in a
direction (X-axis direction) perpendicular to the moving direction
of the stage 10 (Y-axis direction) and the lifting direction of the
Z-slider 43 (Z-axis direction); and an X-axis driving mechanism 48
as a third movement mechanism that drives the X-slider 47 to move
in the X-axis direction.
[0092] In this exemplary embodiment, the contact-type detector 20
and the image probe 30 are attached to the X-slider 47. Therefore,
the relative movement mechanism 40 is provided by a
three-dimensional movement mechanism that includes the Y-axis
driving mechanism 41 that moves the stage 10 in the Y-axis
direction, the Z-axis driving mechanism 44 that moves the
contact-type detector 20 and the image probe 30 in the Z-axis
direction, and the X-axis driving mechanism 48 that moves the
contact-type detector 20 and the image probe 30 in the X-axis
direction.
[0093] Each of the Y-axis driving mechanism 41 and the Z-axis
driving mechanism 44 is provided by, for instance, a feed screw
mechanism (not shown) that includes a ball screw shaft and a nut
member screwed to the ball screw shaft.
[0094] The X-axis driving mechanism 48 includes a driving mechanism
body 48A fixed to the rotary plate 46, a guide rail 48B provided to
the driving mechanism body 48A in parallel to the X-axis direction
to movably support the X-slider 47, a driving source (not shown)
that drives the X-slider 47 to reciprocate along the guide rail
48B, and the like.
[0095] As shown in FIG. 3, the contact-type detector 20 includes a
detector body 21 being hung and supported on the X-slider 47, and a
contact-type probe 22 being supported on the detector body 21 in
parallel to the X-axis direction. The contact-type probe 22
includes a probe body 23, an arm 25 being swingably supported on
the probe body 23 and being provided with the stylus 24 at a tip
end thereof, and a detecting portion 26 that detects a swing amount
of the arm 25.
[0096] The image probe 30 includes a cylindrical probe body 32
being integrally connected to the X-slider 47 via a connecting
member 31 along with the contact-type detector 20, and a probe head
33 being downwardly supported on a tip end of the probe body
32.
[0097] As shown in FIG. 4, the probe head 33 includes an objective
lens 35, an LED 36 as a light source being located on an outer
periphery of the objective lens 35, a CCD sensor 37 that receives
reflected light from the object that has passed through the
objective lens 35 to capture an image of the object, and a cover 38
that covers the LED 36 and the surroundings thereof.
[0098] The image probe 30 is located at a position offset relative
to the contact-type detector 20. Specifically, as shown in FIG. 2,
a focal point of the objective lens 35 of the image probe 30 is
deviated downward in the Z-axis direction from the tip end of the
stylus 24 of the contact-type detector 20 by an offset amount OFz
and rearward in the Y-axis direction from the longitudinal axis of
the stylus 24 by an offset amount OFy. Incidentally, the focal
point is located at the same position in the X-axis direction as
the longitudinal axis of the stylus 24 (i.e., at a position
corresponding to an offset amount OFx=0).
[0099] As shown in FIG. 5, the controller 50 is connected to an
input device 51, a display 52 and a storage 53 in addition to the
relative movement mechanism 40, the contact-type detector 20 and
the image probe 30.
[0100] The input device 51 is provided with, for instance, a
portable keyboard, a joystick or the like and is used not only to
input various kinds of operation commands and data but also to
designate a position at which the stylus 24 is to be set
(measurement starting position) in accordance with the image
captured by the image probe 30.
[0101] The display 52 shows not only the image captured by the
image probe 30 but also profile and/or roughness data obtained by
the contact-type detector 20.
[0102] The storage 53 includes a program storing portion 54 that
stores a measurement program and the like, an offset amount storing
portion 55 as an offset amount storage unit that stores the offset
amounts OFx, OFy and OFz between the stylus 24 of the contact-type
detector 20 and the image probe 30, a data storing portion 56 that
stores image data and measurement data obtained from measurement,
and the like.
[0103] The controller 50 includes: a center position calculating
unit that, when position data of at least three points of a
circular contour of a circular concave portion or circular convex
portion of the object are entered by the image probe 30 in
accordance with the measurement program stored in the program
storing portion 54, approximates the entered position data to a
circle to obtain a center position of the circle; a stylus setting
unit that, when the center position is obtained by the center
position calculating unit, operates the relative movement mechanism
40 to position the stylus 24 of the contact-type detector 20 at the
center position; and a measurement performing unit that operates
the relative movement mechanism 40 to enable relative movement
between the contact-type detector 20 and the object while the
stylus 24 of the contact-type detector 20 is in contact with the
object, thereby measuring the surface texture of the object.
[0104] When the center position is obtained by the center position
calculating unit, the stylus setting unit operates the relative
movement mechanism 40 to position the image probe 30 at the center
position and operates the relative movement mechanism 40 by offset
amounts of OFx, OFy and OFz stored in an offset amount storing
portion 55 to position the stylus 24 of the contact-type detector
20 at the center position.
[0105] The controller 50 further includes an edge detection
function for detecting the edge of the object in the image of the
object captured by the image probe 30, and an auto-focusing
function for displacing the objective lens 35 in a heightwise
direction of the object (Z-axis direction) so that the focal point
of the objective lens is set at the surface of the object defined
in the heightwise direction to detect a heightwise position of the
object depending on the displacement amount of the objective lens
35. The edge detection function may be based on any known principle
of detection but may use, for instance, a technique in which an
average intensity (light intensity) in a direction perpendicular to
the detection direction of the image probe 30 is obtained to detect
a position at which the average intensity becomes equal to or below
a preset threshold as the edge.
<Description of Object (see FIGS. 6A and 6B)>
[0106] An object 60A includes a circular concave portion 61 at a
center thereof. The circular concave portion 61 has a circular
contour and a spherical and concave interior. The circular concave
portion 61 is exemplified by a concave microlens molding surface
formed on a microlens array mold, but not limited to this.
<Description of Measuring Method (see FIGS. 7A to 11)>
[0107] (1) As shown in FIGS. 7A and 7B, the relative movement
mechanism 40 is operated to move the circular concave portion 61 of
the object 60A within a view field 64 of the image probe 30.
[0108] (2) As shown in FIGS. 8A and 8B, in a vicinity of the
circular concave portion 61 of the object 60A, the objective lens
35 of the image probe 30 is automatically focused so as to set the
focal point of the objective lens 35 near the circular concave
portion 61 of the object 60A and data D1, D2, D3 and so on of at
least three points of the circular contour of the circular concave
portion 61 are acquired by using the edge detection function (a
contour data acquisition step).
[0109] (3) As shown in FIG. 9, the controller 50 then approximates
the position data acquired in the contour data acquisition step to
a circle 63 to obtain a center position C of the circle (a circle
approximation step).
[0110] (4) Subsequently, as shown in FIG. 10, the relative movement
mechanism 40 is operated to position the image probe 30 at the
center position C.
[0111] (5) Subsequently, as shown in FIG. 11, the relative movement
mechanism 40 is operated by the offset amounts OFx, OFy and OFz
stored in the offset amount storing portion 55 to position the
stylus 24 of the contact-type detector 20 at the center position C
(a stylus setting step).
[0112] (6) In this state where the stylus 24 of the contact-type
detector 20 is positioned at the center position C of the circular
concave 61 of the object 60A, the relative movement mechanism 40 is
operated to enable relative movement between the stylus 24 of the
contact-type detector 20 and the object 60A (a measuring step).
Thus, the surface texture of the circular concave portion 61 is
measured.
Advantages of First Exemplary Embodiment
[0113] In the surface texture measuring machine including the
contact-type detector 20 having the stylus 24 and the image probe
30 according to the first exemplary embodiment, when the operator
operates the relative movement mechanism 40 to acquire the position
data of at least three point of the circular contour of the
circular concave portion 61 of the object 60A by the image probe
30, the controller 50 approximates the entered position data to the
circle 63 to obtain the center position C of the circle 63, and
then operates the relative movement mechanism 40 to position the
stylus 24 of the contact-type detector 20 at the center position
C.
[0114] In this manner, the stylus 24 of the contact-type detector
20 can be automatically set at the center position C of the
circular concave portion 61 of the object 60A. In other words, the
operator does not have to position the tip end of the stylus at the
circular concave portion while visually checking and adjusting the
position of the tip end of the stylus relative to the circular
concave portion as in a typical apparatus, thereby shortening the
setting time of the stylus.
[0115] The stylus 24 of the contact-type detector 20 and the image
probe 30 are offset from each other in the Z-axis direction and the
Y-axis direction respectively by the offset amounts OFz and OFy.
Thus, during the measurement, the stylus 24 and the image probe 30
can be prevented from being interfered with each other without
providing a mechanism for evacuating one of the stylus 24 and the
image probe 30 that is not used for the measurement.
[0116] Further, the offset amounts OFx, OFy and OFz between the tip
end of the stylus 24 of the contact-type detector 20 and the image
probe 30 are stored in the offset amount storing portion 55.
Accordingly, by calculating the center position C of the circular
concave portion 61, operating the relative movement mechanism 40 to
position the image probe 30 at the center position C and operating
the relative movement mechanism 40 by the offset amounts OFx, OFy
and OFz stored in the offset amount storing portion 55, the stylus
24 of the contact-type detector 20 can be automatically positioned
at the center position C.
[0117] Accordingly, by accurately obtaining the offset amounts OFx,
OFy and OFz between the stylus 24 of the contact-type detector 20
and the image probe 30 in advance, the stylus 24 of the
contact-type detector 20 can be automatically positioned at the
center position C of the circular concave portion 61 with a simple
operation and processing,
[0118] Alternatively, only the image probe 30 can be used for the
measurement.
[0119] For instance, while a width of a line, a diameter of a hole,
or the like can be measured by using an image captured by the image
probe 30, a dimension in an optical-axial direction of the
objective lens 35 (level difference height) or the like can be
measured by using the auto-focusing function of the image probe
30.
[0120] The relative movement mechanism 40 includes the Y-axis
driving mechanism 41 that moves the stage 10 on which the object is
mounted in the Y-axis direction, and the X-axis driving mechanism
48 and the Z-axis driving mechanism 44 that respectively move the
contact-type detector 20 and the image probe 30 in the X-axis
direction and the Z-axis direction. Thus, the relative movement
mechanism 40 enables the object and the contact-type detector 20
and the image probe 30 to move in the three dimensional directions,
i.e., the X-axis direction, the Y-axis direction and the Z-axis
direction that are set perpendicular to one another. Thus, the
profile and surface roughness of the object can be measured
irrespective of an orientation and attitude of a measurement
portion of the object.
[0121] Both the contact-type detector 20 and the image probe 30 are
attached to the X-slider 47 while being offset from each other.
Thus, there can be provided a simple and low-cost structure as
compared with a device in which a mechanism is provided for
separately moving the contact-type detector 20 and the image probe
30.
[0122] The image probe 30 includes the objective lens 35, the LED
36 as a light source being located on the outer periphery of the
objective lens 35, and the CCD sensor 37 that receives reflected
light from the object that has passed through the objective lens
35. Thus, the CCD sensor 37 can highly accurately obtain the image
of the surface of the object through the objective lens 35. In
addition, since the LED 36 is located around the objective lens 35,
the image probe 30 can be downsized as compared with a case where a
lighting device is separately provided.
Modifications of First Exemplary Embodiment (see FIGS. 12 to
17)
[0123] The object to be measured is not limited to the object shown
in FIGS. 6A and 6B. For instance, the object may be an object 60B
including a circular convex portion 62 at a center thereof. The
circular convex portion 62 has a circular contour and a spherical
and convex interior.
[0124] A surface texture of the circular convex portion 62 of the
object 60B is measured as shown in FIGS. 13 to 17.
[0125] (11) As shown in FIG. 13, the relative movement mechanism 40
is operated to move the circular convex portion 62 of the object
60B within a view field 64 of the image probe 30.
[0126] (12) As shown in FIGS. 14A and 14B, in the vicinity of the
circular convex portion 62 of the object 60B, the objective lens 35
of the image probe 30 is automatically focused so as to set the
focal point of the objective lens 35 near the circular convex
portion 62 of the object 60B and data D1, D2, D3 and so on of at
least three points of the circular contour of the circular convex
portion 62 are acquired by using the edge detection function. This
operation is repeated three times or more in total at other
positions where the circular convex portion 62 of the object 60B is
within the visual field of the image probe 30 (see FIG. 15) (a
contour data acquisition step).
[0127] (13) As shown in FIG. 16, the controller 50 then
approximates the position data acquired in the contour data
acquisition step to the circle 63 to obtain the center position C
of the circle (a circle approximation step).
[0128] (14) Subsequently, the relative movement mechanism 40 is
operated to position the image probe 30 at the center position
C.
[0129] (15) As shown in FIG. 17, the relative movement mechanism 40
is operated by the offset amounts OFx, OFy and OFz stored in the
offset amount storing portion 55 to position the stylus 24 of the
image probe 20 at the center position C (a stylus setting
step).
[0130] (16) In this state where the stylus 24 of the contact-type
detector 20 is positioned at the center position C of the circular
convex 62 of the object 60B, the relative movement mechanism 40 is
operated to enable relative movement between the stylus 24 of the
contact-type detector 20 and the object 60B (a measuring step).
Thus, the surface texture of the circular convex portion 62 is
measured.
[0131] It should be noted that the accuracy of this measurement is
expected to be improved by calculating an inclination (an
inclination relative to the horizon) of the object 60B based on the
automatically-focused data in the heightwise direction of the
object 60B (Z-axis direction) and changing the attitude of the
object 60B, when the automatic focus and the edge detection are
performed in three other positions where the circular convex
portion 62 of the object 60B is located within the visual field of
the image probe 30. The attitude of the object 60B can be changed
by inserting an inclined table between the stage 10 and the object
60B and moving the inclined table.
[0132] Though the contact-type detector 20 includes the arm 25
being provided with the stylus 24 at the tip end thereof and the
detecting portion 26 that detects the swing amount of the arm 25,
the contact-type detector 20 may have any other arrangement as long
as the surface profile and roughness of an object can be measured
while the stylus 24 is in contact with the object.
[0133] Though the image probe 30 includes the probe head 33 being
provided with the objective lens 35, the LED 36 as a light source
being located on the outer periphery of the objective lens 35 and
the CCD sensor 37 that receives reflected light from the object
that has passed through the objective lens 35 to capture the image
of the object, the invention is not limited thereto.
[0134] For instance, the LED 36 as a light source may be provided
separately from the image probe. Furthermore, the objective lens 35
may be replaceable so that the objective lens 35 is replaced with
one having a different magnification, so that an appropriate
operation can be performed depending on the size of the measurement
area on the object.
[0135] While the relative movement mechanism 40 enables the stage
10 to move in the Y-axis direction and the contact-type detector 20
and the image probe 30 to move in the X-axis direction and the
Z-axis direction, the invention is not limited thereto. In other
words, as long as the stage 10, and the contact-type detector 20
and the image probe 30 are movable in the three dimensional
directions, either one of the stage 10 and the contact-type
detector 20 and the image probe 30 may be movable.
[0136] Alternatively, the contact-type detector 20 and the image
probe 30 may be associated with their respective relative movement
mechanisms so that the contact-type detector 20 and the image probe
30 are independently moved.
Second Exemplary Embodiment
[0137] It should be noted that components which are identical or
correspond to those of the first exemplary embodiment will be
denoted by the same reference numerals, description of which will
be omitted, for describing a second exemplary embodiment.
[0138] A surface texture measuring machine according to the second
exemplary embodiment can adjust the attitude of the object in
parallel to or perpendicular to a predetermined measurement axis.
As shown in FIGS. 20 and 21, a turntable 10A is added to the
surface texture measuring machine according the first exemplary
embodiment.
[0139] The turntable 10A is mounted on the stage 10 and rotated by
a command from the controller 50. Thus, an object W is rotated
within a horizontal plane (an XY plane). The object W is
cylindrical in the second exemplary embodiment.
[0140] The image probe 30 includes a component for positioning the
object W at the focal point of the objective lens 35 as needed in
addition to the above components. When the relative position
between the image probe 30 and the object W is to be determined,
for instance, by a so-called pinhole method, the image probe 30
includes a tube lens provided at a downstream of an optical path of
the objective lens 35, and photodiodes respectively provided on a
front side and a rear side of a focal point of the tube lens. The
image probe 30 is moved by the controller 50 via the relative
movement mechanism 40 in a vertical direction relative to the
object W so as to equalize the amounts of light received by the
respective photodiodes to be positioned where the object W is
located at the focal point of the objective lens 35.
[0141] Alternatively, when the relative position between the image
probe 30 and the object W is to be determined by a so-called
contrast method, the image probe 30 includes a light source
projecting a predetermined pattern onto the object W via a
projection plate and an objective lens, The image probe 30 captures
the predetermined pattern projected on the object W. In addition,
the image probe 30 is moved by the controller 50 via the relative
movement mechanism 40 in a vertical direction relative to the
object W based on a contrast of the captured pattern image, and is
positioned where the object W is located at the focal point of the
objective lens 35.
[0142] In such a surface texture measuring machine, when the
attitude of the object W is inclined relative to the measurement
axis during an actual measurement, the stylus 24 is displaced in an
outer circumferential direction of the cylindrical object W as well
as in an axial direction of the object W. Accordingly, a
measurement value includes a value showing a cylindrical outer
circumferential profile, thereby causing an error in a measurement
result. Accordingly, in order to prevent generation of such an
error, the controller 50 includes an image probe control unit 50A,
an inclination angle calculating unit 50B and an attitude adjusting
unit 50C. These units 50A to 50C perform a preliminary measurement
in advance of an actual measurement and adjust the attitude of the
object W, for instance, in parallel to the measurement axis.
[0143] An attitude adjustment method of the object W by the
respective units 50A to 50C will be described as follows.
[0144] FIG. 22 is a flow chart for showing the attitude adjustment
method. FIG. 23 is a plan view showing the image probe 30 and the
object W.
[0145] Firstly, the operator controls the relative movement
mechanism 40 by operating the input device 51 and moves the image
probe 30 above the object W.
[0146] Under this state, when a command from the input device 51 is
entered through the input device 51 operated by the operator, the
image probe control unit 50A moves the image probe 30 in a vertical
direction (a Z axis direction) by controlling the relative movement
mechanism 40 and positions the object W at the focal point of the
objective lens 35 to capture an image of the object W by the image
probe 30 (an image capture step S1). As a focusing method of the
image probe 30 by the image probe control unit 50A in this step,
any method such as the pinhole method and the contrast method as
described above is applicable as needed.
[0147] After the step S1, the inclination angle calculating unit
50B calculates a generatrix B of the object W from an outer profile
of the object W based on the captured image of the object W to
calculate an inclination angle .theta. of the generatrix B relative
to the measurement axis A as an inclination angle .theta. of the
object W relative to the measurement axis A (an inclination angle
calculation step S2).
[0148] FIG. 24 is a plan view showing an attitude adjustment of the
object W by the attitude adjusting unit 50C.
[0149] After the step S2, the attitude adjusting unit 50C rotates
the turntable 10A based on the inclination angle .theta. and
adjusts the attitude of the object W in parallel to the measurement
axis A (an adjustment step S3). Accordingly, the attitude of the
object W is adjusted in parallel to the measurement axis A, thereby
carrying out the actual measurement with high accuracy.
[0150] FIG. 25 is a plan view showing the actual measurement by the
controller 50.
[0151] After the attitude of the object W is adjusted as described
above, the controller 50 controls the relative movement mechanism
40 to move the stylus 24 to the inputted measurement starting
position. Next, the controller 50 controls the X-axis driving
mechanism 48 and moves the stylus 24 from the measurement starting
position to an inputted measurement end position along the
measurement axis A, thereby measuring the surface texture of the
object W along the axial direction.
[0152] As described above, in order to measure the surface texture
of the object W along the axial direction at the actual
measurement, the respective units 50A to 50C perform the so-called
alignment, by which the attitude of the object W is adjusted in
parallel to the measurement axis A. However, in order to measure
the surface texture along a direction perpendicular to the axial
direction of the object W in the actual measurement, the respective
units 50A to 50C perform a so-called right angling, by which the
attitude of the object W is adjusted perpendicular to the
measurement axis A, in the same manner as that in the alignment.
The right-angling of the object W by the respective units 50A to
50C will be simply described as follows.
[0153] FIG. 26 is a plan view showing the image probe 30 that
captures the object W.
[0154] Firstly, the image probe control unit 50A captures the image
of the object W by the image probe 30 (the image capture step S1).
Next, the inclination angle calculating unit 50B calculates the
inclination angle .theta. of the object W relative to the
measurement axis A based on the captured image of the object W (the
inclination angle calculation step S2).
[0155] FIG. 27 is a plan view showing an attitude adjustment of the
object W by the attitude adjusting unit 50C.
[0156] The attitude adjusting unit 50C rotates the turntable 10A
based on the inclination angle .theta. and adjusts the attitude of
the object W perpendicular to the measurement axis A (the
adjustment step S3). Thus, the right-angling is completed.
Subsequently, the controller 50 moves the stylus 24 along the
measurement axis A, thereby measuring the surface texture of the
object W along a direction perpendicular to the axial
direction.
Advantages of Second Exemplary Embodiment
[0157] According to the second exemplary embodiment, what is
carried out in the preliminary measurement is only that the image
probe 30 captures the image of the object W to calculate the
inclination angle .theta. of the object W relative to the
measurement axis A. Accordingly, the number of the steps in the
preliminary measurement can be decreased, thereby shortening the
time for the preliminary measurement. Moreover, since the
measurement is carried out by the image probe 30, the measurement
time can be shortened as compared with the measurement by the
stylus 24. Consequently, the time for the preliminary measurement
can be considerably shortened.
[0158] Further, since the preliminary measurement is a noncontact
measurement by the image probe 30, the object W is not damaged.
Modification(s) of Second Exemplary Embodiment
[0159] A table mounted on the stage is not limited to the table
shown in FIG. 20.
[0160] For instance, the surface texture measuring mechanism as
shown in FIG. 28 may be provided with a leveling table 10B in place
of the turntable 10A.
[0161] On the leveling table 10B shown in FIG. 28, a rectangular
parallelepiped object W is mounted. The leveling table 10B inclines
the object W relative to a horizontal plane which is a reference
plane perpendicular to a displacing direction (vertical direction)
of the stylus 24. In advance of the actual measurement, the
respective units 50A to 50C of the controller 50 shown in FIG. 29
perform a so-called leveling by which the attitude of the object W
is adjusted so as to horizontalize a to-be-measured surface S.
[0162] The leveling of the object W by the respective units 50A to
50C will be briefly explained with reference to the flow chart in
FIG. 30 and the side elevations showing movement of the leveling
table 10B in FIGS. 31A and 31B. FIG. 31A shows the leveling table
10B that is horizontally situated. FIG. 31B shows the leveling
table 10B inclined at an angle where the to-be-measured surface S
is horizontal.
[0163] Firstly, as shown in FIG. 31A, the operator controls the
relative movement mechanism 40 via the input device 51 and moves
the image probe 30 above points (for instance, three points) of the
to-be-measured surface S. At each of the points, the image probe
control unit 50A moves the image probe 30 in a vertical direction
by the relative movement mechanism 40 so that the each of the
points is positioned at the focal point of the objective lens 35 (a
focusing step SA1). At this time, a height of the image probe 30 at
the each of the points is detected by a sensor (not shown) provided
in the Z-axis driving mechanism 44. In this arrangement, the image
probe control unit 50A is a focusing unit.
[0164] After the step SA1, the inclination angle calculating unit
50B calculates the inclination angle .theta. of the to-be-measured
surface S relative to the horizontal plane based on the height of
the image probe 30 at the each of the points of the to-be-measured
surface S (an inclination angle calculation step SA2).
[0165] After the step SA2, as shown in FIG. 31B, the attitude
adjusting unit 50C rotates the leveling table 10B based on the
inclination angle .theta. and adjusts the attitude of the object W
so that the to-be-measured surface S thereof is horizontal (the
adjustment step SA3). Thus, the leveling is completed.
Subsequently, the controller 50 moves the stylus 24 along the
measurement axis A, thereby measuring the surface texture of the
object W. It should be noted that the leveling table 10B is
schematically shown in FIGS. 28 and 31 and is rotatable in a
counterclockwise direction.
[0166] Even with the above arrangement, what is carried out in the
preliminary measurement is only that the image probe 30 is
automatically focused at each of the points of the to-be-measured
surface S and the inclination angle .theta. of the to-be-measured
surface S relative to the horizontal plane based on the height of
the image probe 30 is calculated at each of the points.
Accordingly, the number of the steps in the preliminary measurement
can be reduced. Moreover, since the measurement is carried out by
the image probe 30, the measurement time can be considerably
shortened as compared with a typical measurement by the stylus 24.
Further, since the preliminary measurement is a noncontact
measurement by the image probe 30, the object W is not damaged.
[0167] In this exemplary embodiment, a profile of the object of
which attitude is adjustable is not limited to the above-mentioned
profile. In this exemplary embodiment, an attitude of the object
having any profile is adjustable. Further, the surface texture
measuring machine according to the exemplary embodiment may include
a table functioning as the turntable and the leveling table, by
which the surface texture measuring machine according to the
exemplary embodiment adjusts the attitude of the object in parallel
to the measurement axis and adjusts the to-be-measured surface so
that the to-be-measured surface is horizontal.
Third Exemplary Embodiment
[0168] It should be noted that components which are identical or
correspond to those of the first exemplary embodiment will be
denoted by the same reference numerals, description of which will
be omitted, for describing a third exemplary embodiment,
[0169] A surface texture measuring machine according the third
exemplary embodiment can automatically set a stylus of a
contact-type detector at a measurement starting position of an
object based on an image of the object captured by an image probe.
As shown in FIGS. 32 and 33, the image probe 30 and the controller
50 are different in a structure from those of the surface texture
measuring machine according the first exemplary embodiment.
[0170] The image probe 30 of the third exemplary embodiment
includes: a cylindrical probe body 32 that is integrally connected
to the X-slider 47 via the connecting member 31 along with the
contact-type detector 20; and the probe head 33 that is rotatably
supported around an axis (Y-axis) perpendicular to a direction
(Y-axis direction) in which the contact-type detector 20 and the
stage 10 relatively move and the displacing direction of the stylus
24 (Z-axis direction: vertical direction) while the stylus 24 is in
contact with the object, the probe head 33 being provided at a tip
end of the probe body 32; and a head turning mechanism 34 such as a
motor for rotating the probe head 33.
[0171] The controller 50 according to the third exemplary
embodiment includes: a movement course calculating unit that, when
the measurement starting position is designated based on the image
of the object captured by the image probe 30 in accordance with the
measurement program stored in the program storing portion 54,
calculates and stores the movement course of the relative movement
mechanism 40 so that the stylus 24 of the contact-type detector 20
is brought into contact with the measurement starting position on
the object; a stylus setting unit that drives the relative movement
mechanism 40 along the movement course calculated by the movement
course calculating unit; and a measurement performing unit that
operates the relative movement mechanism 40 so that the
contact-type detector 20 is moved relative to the object while the
stylus 24 of the contact-type detector 20 is in contact with the
object, thereby measuring the surface profile of the object.
[0172] The controller 50 further includes an edge detection
function for detecting the edge of the object in the image of the
object captured by the image probe 30, and an auto-focusing
function for displacing the objective lens 35 in the heightwise
direction of the object (Z-axis direction) so that the focal point
of the objective lens is set at the surface of the object defined
in the heightwise direction to detect the heightwise position of
the object depending on the displacement amount of the objective
lens 35. The edge detection function may be based on any known
principle of detection but may use, for instance, a technique in
which an average intensity (light intensity) in a direction
perpendicular to the detection direction of the image probe 30 is
obtained to detect a position at which the average intensity
becomes equal to or below a preset threshold as the edge.
<Description of Measuring Method (see FIGS. 34 to 37)>
[0173] For instance, a measurement of an object 80 shown in FIG. 34
will be described.
[0174] The object 80 includes: a horizontal wall 81; a vertical
wall 82 perpendicularly erected at one end of the horizontal wall
81; and an inclined wall 83 formed in an inclined manner between
the horizontal wall 81 and the vertical wall 82. Four holes 82A to
82D are formed on both ends of the vertical wall 82 interposing the
inclined wall 83. Two holes 81A and 81B are formed on both ends of
the horizontal wall 81. A hole 83A is formed at a center of the
inclined wall 83 in a manner perpendicular to the inclined wall
83.
Example of Profile Measurement of Holes 82A to 82D on Vertical Wall
82
[0175] Firstly, as shown in FIG. 35A, the probe head 33 of the
image probe 30 is held in a horizontal attitude by a command of the
input device 51, In this state, the image probe 30 captures an
image of the vertical wall 82 of the object 80. The image data of
the vertical wall 82 of the object 80 is stored in the data storing
portion 56 and then is displayed on the display 52.
[0176] When a measurement starting position (a position at which
the stylus 24 of the contact-type detector 20 is first brought into
contact), for instance, a lower inner-circumferential surface of
the hole 82A, is designated by using the input device 51 based on
the image of the vertical wall 82 on the display 52, the controller
50 calculates the movement course of the relative movement
mechanism 40 in consideration of the offset amounts OFx, OFy and
OFz stored in the offset amount storing portion 55 so that the
stylus 24 of the contact-type detector 20 is brought into contact
with the lower inner-circumferential surface of the hole 82A on the
object 80. The calculated movement course is stored in the program
storing portion 54.
[0177] Subsequently, upon receiving a command for starting a
measurement, the controller 50 operates the relative movement
mechanism 40 in accordance with the movement course stored in the
program storing portion 54. In other words, as shown in FIG. 35B,
the controller 50 operates the relative movement mechanism 40 so
that the stylus 24 of the contact-type detector 20 is brought into
contact with the designated position (the lower
inner-circumferential surface of the hole 82A).
[0178] When the stylus 24 of the contact-type detector 20 is set at
the lower inner-circumferential surface of the hole 82A, the
controller 50 operates the X-axis driving mechanism 48. Then, the
stylus 24 of the contact-type detector 20 is moved from the
designated position in the X-axis direction. With this movement,
the stylus 24 is vertically displaced in accordance with the
surface roughness of the object 80 in contact with the stylus 24
and the displacement amount of the stylus 24 is detected by the
detecting portion 26. Consequently, the surface roughness of the
hole 82A of the object 80 is measured according to the displacement
amount and the movement amount of the stylus 24.
Example of Profile Measurement of Hole 83A on Inclined Wall 83
[0179] Firstly, as shown in FIG. 36A, the probe head 33 of the
image probe 30 is rotated by a command of the input device 51 and
is held in an attitude opposing the inclined wall 83. In this
state, the image probe 30 captures an image of the inclined wall 83
of the object 80. Then, the image data of the inclined wall 83 of
the object 80 is stored in the data storing portion 56 and then is
displayed on the display 52.
[0180] When a measurement starting position, for instance, a lower
inner-circumferential surface of the hole 83A, is designated by
using the input device 51 based on the image of the inclined wall
83 displayed on the display 52, the controller 50 calculates the
movement course of the relative movement mechanism 40 in
consideration of the offset amounts OFz and OFy stored in the
offset amount storing portion 55 so that the stylus 24 of the
contact-type detector 20 is brought into contact with the lower
inner-circumferential surface of the hole 83A on the object 80. The
calculated movement course is stored in the program storing portion
54.
[0181] Subsequently, upon receiving a command for starting a
measurement, the controller 50 operates the relative movement
mechanism 40 in accordance with the movement course stored in the
program storing portion 54. In other words, as shown in FIG. 36B,
the controller 50 inclines the X-axis driving mechanism 48 by
rotating the rotation mechanism 45, thereby aligning the
inclination of the hole 83A with the moving direction of X-axis
driving mechanism 48. Subsequently, the controller 50 operates the
relative movement mechanism 40 so that the stylus 24 of the
contact-type detector 20 is brought into contact with the
designated lower inner-circumferential surface of the hole 83A.
[0182] When the stylus 24 of the contact-type detector 20 is set at
the designated position, the controller 50 operates the X-axis
driving mechanism 48. Then, the stylus 24 of the contact-type
detector 20 is moved from the designated position in an axial
direction of the hole 83A. With this movement, the stylus 24 is
vertically displaced in accordance with the surface roughness of
the object 80 in contact with the stylus 24 and the displacement
amount of the stylus 24 is detected by the detecting portion 26.
Consequently, the surface roughness of the hole 83A of the object
80 is measured according to the displacement amount and the
movement amount of the stylus 24.
Example of Profile Measurement of Holes 81A and 8113 on Horizontal
Wall 81
[0183] Firstly, as shown in FIG. 37, the probe head 33 of the image
probe 30 is rotated by a command of the input device 51 and is held
in a downward attitude. In this state, when the image probe 30
captures an image of the horizontal wall 81 of the object 80, the
image data of the horizontal wall 81 of the object 80 is stored in
the data storing portion 56 and then is displayed on the display
52.
[0184] Here, the controller 50 executes processing on the image of
the horizontal wall 81 of the object 80 stored in the data storing
portion 56 to measure profiles and sizes of the holes 81A and
81B.
Advantages of Third Exemplary Embodiment
[0185] A surface texture measuring machine according to the third
exemplary embodiment includes the contact-type detector 20 provided
with the stylus 24 that is brought into contact with a surface of
an object and the image probe 30 that captures an image of the
surface of the object. With this arrangement, after the image probe
30 captures the image of the object, the stylus 24 of the
contact-type detector 20 can be automatically brought into contact
with a measurement position on the object based on the captured
image of the object. Accordingly, the operator is not required to
set a tip end of the stylus at a measurement starting position of
the object while visually checking and adjusting the position of
the tip end of the stylus relative to the measurement starting
position as in a typical apparatus. Therefore, the stylus can be
prevented from interfering with the object while reducing the
burden on the operator.
[0186] The offset amounts OFz and OFy between the tip end of the
stylus 24 of the contact-type detector 20 and the image probe 30
are stored in the offset amount storing portion 55. These offset
amounts stored in the offset amount storing portion 55 are taken
into consideration in calculating the movement course of the
relative movement mechanism 40 so that the stylus 24 of the
contact-type detector 20 is brought into contact with the
measurement starting position on the object. Since the relative
movement mechanism 40 is operated in accordance with this
measurement course, the stylus 24 of the contact-type detector 20
can be accurately brought into contact with the measurement
starting position on the object.
[0187] The image probe 30 includes: the cylindrical probe body 32
that is integrally connected to the X-slider 47 along with the
contact-type detector 20; the probe head 33 that is rotatably
supported around an axis in parallel to the Y-axis, the probe head
33 being provided at the tip end of the probe body 32; and the head
turning mechanism 34 such as a motor for rotating the probe head
33. Accordingly, the downward attitude of the probe head 33 can be
changed to the horizontal attitude thereof by the head turning
mechanism 34.
[0188] Accordingly, the image of the vertical surface or any
inclined surface as well as the horizontal surface of the object
can be captured so that a profile of a hole or a protrusion
provided on such surfaces can be measured by the contact-type
detector 20.
* * * * *